1. Field of the Invention
The present invention relates generally to layout of the optical path in the image-capturing system, and more particularly to an optimum layout of the optical path in the image-capturing system and the method for forming the same.
2. Description of the Prior Art
Recently, there are various digital products that have been developed within the industry, such as notebooks, Personal Digital Assistants (PDA), and Consumption-Communication-Computers (3C). Usually, these digital products include or connect with a monitor to display an image, such as liquid crystal display (LCD) or liquid crystal panel. For the image processing apparatus, in addition, they can be classed as a motionless-image processing apparatus, such as digital camera, scanner, and a moving-image processing apparatus, such as digital video camera.
In the image-processing apparatus, the image-capturing system is the most important member, wherein the image-capturing system is one of the products concerning optical principle that comprises various components, such as image-capturing system, reflector, lens. Generally, the image-capturing system includes a charge-coupled device (CCD) that is sensitive to light, and it can transform photosensitivity of each pixel device into image datum and store them.
In light of the scanner, conventional image-capturing system captures the image by moving the signal image-capturing apparatus and reflection of mirrors. When the light is reflected from the image on the sensitive surface of the charge-coupled device (CCD), a semiangle (θ/2) can be generated. Generally, the sensitive surface of the charge-coupled device (CCD) is a straight surface, and it is not an arc surface. Therefore, the sensitive surface of the charge-coupled device(CCD )cannot receive the reflecting light when the semiangle (θ/2) becomes over large. In view of this, the semiangle (θ/2) has to be decreased so as to completely receive the reflecting light by the charge-coupled device (CCD), wherein one of the method for decreasing the semiangle (θ/2) is to increase the optical paths. Furthermore, the longer the length of the optical paths, the smaller the semiangle (θ/2). In the same way, the longer the length of the optical paths, the smaller the sensitive surface of the charge-coupled device (CCD), so that the whole volume also can be decreased. Therefore, the image-capturing system with the longer optical path reduces the cost for fabricating the image-capturing module and easy to make it.
Moreover, the image-capturing module, the reflectors and the lens are arranged in the peripheral region of conventional image-capturing system. Referring to FIG. 1, the image-capturing system 100 comprises a case 110 with a layout region 110A for optical path, and a module region 110B therein, wherein the mirrors 120A to 120C are set in the layout region 110A; and further, the lens 130 and the image-capturing module 140 are set in the module region 110B. In general, the layout region 110A for optical path is located on the peripheral region of the case 110, which is only the space for being applied to the layout of optical path, and the methods for layout of optical path are difference among the various sizes of the circular diameter (Ø) of the lens. Therefore, if the sizes of the image-capturing module 140 and the lens 130 are greater, they will occupy the major portion of space in the case 110 of the image-capturing system 100 that results in the limitation of length in layout for optical path.
In accordance with the above description, a new optimum layout of the optical path in the image-capturing system and the method for forming the same is therefore necessary to reduce the requirement for space of the image-capturing system, so as to decrease the fabricative cost and easy to make it; and further, this invention can strengthen and raise the scanning quality.